In the early 1930s, when major studios continued to codify many of the conventions of modern horror, Walt Disney made some notable contributions, including "The Mad Doctor," a short subject from 1933. Some truly macabre moments emerge, and the titular mad doctor truly is, well, mad, as evidenced by his escalating levels of sadism. Only the "it was all a bad dream" ending can save Pluto from a nasty, ugly fate. Dig what happens to his shadow!
For comparative purposes, also check out "The Runaway Brain," a 1995 short that revisits the mad scientist theme.
The Crimson Ghost (1946) - *The Crimson Ghost (1946) *
46 minutes ago